The Bharatiya Janata Party (BJP) big guns in Delhi may not spare a chance of firing a salute at the Calcutta Metro Railway, but the underground network here seems to have hit a roadblock.

Work on the proposed Metro Rail extension, between Tollygunge and Garia, has ground to a halt with contractors engaged in dredging Tolly’s Nullah refusing to carry on. They announced on Friday that the extension work on the 8.7-km stretch was being held up by the accumulation of silt in the canal. “It is impossible to make any headway till the silt is cleared,” said Nantu Sarkar, one of the contractors.

This, a day after BJP parliamentarian Madan Lal Khurana had taken deputy Prime Minister L.K. Advani’s track to shower praise on the Calcutta Metro for its cleanliness and efficiency.

Ashok Gupta, chief engineer, Metro Railway, meanwhile, said: “We don’t want contractors to stop the work at any cost, since we have to meet a deadline… We have taken up the matter with the Calcutta Metropolitan Development Authority and the Calcutta Metropolitan Water and Sanitation Authority.”

The reluctance on the part of nearly 250 shop-owners to shift out of the Garia market has also proved a hurdle for the extension work. The shop-owners have made it clear that they will not vacate the spot till they are provided with a “proper alternative site”. Biren Ghosh, CPM councillor and Borough 11 chairman from Garia, said: “The shop-owners have a genuine grievance and we have raised the matter with railway minister Nitish Kumar.”